The ADS All-Sky Survey

The ADS All-Sky Survey (ADSASS) is an ongoing effort aimed at turning the NASA Astrophysics Data System (ADS), widely known for its unrivaled value as a literature resource for astronomers, into a data resource. The ADS is not a data repository per se, but it implicitly contains valuable holdings of astronomical data, in the form of images, tables and object references contained within articles. The objective of the ADSASS effort is to extract these data and make them discoverable and available through existing data viewers. The resulting ADSASS data layer promises to greatly enhance workflows and enable new research by tying astronomical literature and data assets into one resource.Astronom

WorldWide Telescope in Research and Education

The WorldWide Telescope computer program, released to researchers and the public as a free resource in 2008 by Microsoft Research, has changed the way the ever-growing Universe of online astronomical data is viewed and understood. The WWT program can be thought of as a scriptable, interactive, richly visual browser of the multi-wavelength Sky as we see it from Earth, and of the Universe as we would travel within it. In its web API format, WWT is being used as a service to display professional research data. In its desktop format, WWT works in concert (thanks to SAMP and other IVOA standards) with more traditional research applications such as ds9, Aladin and TOPCAT. The WWT Ambassadors Program (founded in 2009) recruits and trains astrophysically-literate volunteers (including retirees) who use WWT as a teaching tool in online, classroom, and informal educational settings. Early quantitative studies of WWTA indicate that student experiences with WWT enhance science learning dramatically. Thanks to the wealth of data it can access, and the growing number of services to which it connects, WWT is now a key linking technology in the Seamless Astronomy environment we seek to offer researchers, teachers, and students alike.Astronom

FLAMINGOS Spectroscopy of New Low-Mass Members of the Young Cluster IC 348

We present spectroscopy of candidate stellar and substellar members of the young cluster IC 348. Using the Florida Multi-Object Imaging Near-Infrared Grism Observational Spectrometer with the 4 meter telescope at Kitt Peak National Observatory, we have obtained multi-object moderate-resolution (R=1000) J- and H-band spectra of 66 infrared sources (H=12-17) toward IC 348, many of which are difficult to observe spectroscopically at optical wavelengths (I>20) because they are highly reddened and/or intrinsically cool and red. We have also observed 19 known cluster members that have optical spectral types available from previous work. By using these latter sources as the spectral classification standards, we have identified 14 new members of the cluster with types of M2-M6 in the sample of 66 new objects. Two additional objects exhibit types of >M8.5, but cannot be conclusively classified as either field dwarfs or cluster members with available data. We have estimated extinctions, luminosities, and effective temperatures for these 16 M-type objects, placed them on the H-R diagram, and used the evolutionary models of Chabrier & Baraffe to estimate their masses. If the two candidates at >M8.5 are indeed members, they should be among the least massive known brown dwarfs in IC 348 (M/M_sun~0.01).Comment: 15 pages, The Astrophysical Journal, 2004, v618 (January 10

The Luminosity & Mass Function of the Trapezium Cluster: From B stars to the Deuterium Burning Limit

We use the results of a new, multi-epoch, multi-wavelength, near-infrared census of the Trapezium Cluster in Orion to construct and to analyze the structure of its infrared (K band) luminosity function. Specifically, we employ an improved set of model luminosity functions to derive this cluster's underlying Initial Mass Function (IMF) across the entire range of mass from OB stars to sub-stellar objects down to near the deuterium burning limit. We derive an IMF for the Trapezium Cluster that rises with decreasing mass, having a Salpeter-like IMF slope until near ~0.6 M_sun where the IMF flattens and forms a broad peak extending to the hydrogen burning limit, below which the IMF declines into the sub-stellar regime. Independent of the details, we find that sub-stellar objects account for no more than ~22% of the total number of likely cluster members. Further, the sub-stellar Trapezium IMF breaks from a steady power-law decline and forms a significant secondary peak at the lowest masses (10-20 times the mass of Jupiter). This secondary peak may contain as many as \~30% of the sub-stellar objects in the cluster. Below this sub-stellar IMF peak, our KLF modeling requires a subsequent sharp decline toward the planetary mass regime. Lastly, we investigate the robustness of pre-main sequence luminosity evolution as predicted by current evolutionary models, and we discuss possible origins for the IMF of brown dwarfs.Comment: 74 pages, 30 figures, AASTeX5.0. To be published in the 01 July 2002 ApJ. For color version of figure 1 and online data table see http://www.astro.ufl.edu/~muench/PUB/publications.htm

Evidence for Circumstellar Disks around Young Brown Dwarfs in the Trapezium Cluster

We report the results of deep infrared observations of brown dwarf candidates in the Trapezium cluster in Orion. Analysis of the JHK color-color diagram indicates that a large fraction (approx 65% +/- 15%) of the observed sources exhibit infrared excess emission. This suggests the extreme youth of these objects and in turn, provides strong independent confirmation of the existence of a large population of substellar objects in the cluster. Moreover, this suggests that the majority of these substellar objects are presently surrounded by circumstellar disks similar to the situation for the stellar population of the cluster. This evidence for a high initial disk frequency (> 50%) around cluster members of all masses combined with the smooth continuity of the cluster's initial mass function across the hydrogen burning limit suggests that a single physical mechanism is likely responsible for producing the entire cluster mass spectrum down to near the deuterium burning limit. The results may also indicate that even substellar objects are capable of forming with systems of planetary companions.Comment: 6 pages, 2 figures. Accepted to ApJ Letter

The nature of the dense core population in the pipe nebula: core and cloud kinematics from C18O observations

We present molecular-line observations of 94 dark cloud cores identified in the Pipe nebula through near-IR extinction mapping. Using the Arizona Radio Observatory 12m telescope, we obtained spectra of these cores in the J=1-0 transition of C18O. We use the measured core parameters, i.e., antenna temperature, linewidth, radial velocity, radius and mass, to explore the internal kinematics of these cores as well as their radial motions through the larger molecular cloud. We find that the vast majority of the dark extinction cores are true cloud cores rather than the superposition of unrelated filaments. While we identify no significant correlations between the core's internal gas motions and the cores' other physical parameters, we identify spatially correlated radial velocity variations that outline two main kinematic components of the cloud. The largest is a 15pc long filament that is surprisingly narrow both in spatial dimensions and in radial velocity. Beginning in the Stem of the Pipe, this filament displays uniformly small C18O linewidths (dv~0.4kms-1) as well as core to core motions only slightly in excess of the gas sound speed. The second component outlines what appears to be part of a large (2pc; 1000 solar mass) ring-like structure. Cores associated with this component display both larger linewidths and core to core motions than in the main cloud. The Pipe Molecular Ring may represent a primordial structure related to the formation of this cloud.Comment: Accepted to ApJ. 14 pages, 11 figures. Complete table at end of documen

Identifying Primordial Substructure in NGC 2264

We present new Spitzer Space Telescope observations of the young cluster NGC2264. Observations at 24 micron with the Multiband Imaging Photometer has enabled us to identify the most highly embedded and youngest objects in NGC2264. This letter reports on one particular region of NGC2264 where bright 24 micron sources are spatially configured in curious linear structures with quasi-uniform separations. The majority of these sources (~60% are found to be protostellar in nature with Class I spectral energy distributions. Comparison of their spatial distribution with sub-millimeter data from Wolf-Chase (2003) and millimeter data from Peretto et al. (2005) shows a close correlation between the dust filaments and the linear spatial configurations of the protostars, indicating that star formation is occurring primarily within dense dusty filaments. Finally, the quasi-uniform separations of the protostars are found to be comparable in magnitude to the expected Jeans length suggesting thermal fragmentation of the dense filamentary material.Comment: Accepted for publication in ApJL, 5 pages, 4 figures. Color version available from the following webpages: http://cfa-www.harvard.edu/~pteixeir/ and http://cfa-www.harvard.edu/~clada

Modeling the Near-Infrared Luminosity Functions of Young Stellar Clusters

We present the results of numerical experiments designed to evaluate the usefulness of near-infrared luminosity functions for constraining the Initial Mass Function (IMF) of young stellar populations. From this numerical modeling, we find that the luminosity function of a young stellar population is considerably more sensitive to variations in the underlying initial mass function than to either variations in the star forming history or assumed pre-main-sequence (PMS) mass-to-luminosity relation. To illustrate the potential effectiveness of using the KLF of a young cluster to constrain its IMF, we model the observed K band luminosity function of the nearby Trapezium cluster. Our derived mass function for the Trapezium spans two orders of magnitude in stellar mass (5 Msun to 0.02 Msun), has a peak near the hydrogen burning limit, and has an IMF for Brown Dwarfs which steadily decreases with decreasing mass.Comment: To appear in ApJ (1 April 2000). 37 pages including 11 figures, AAS: ver 5.